Question 13.
Write short notes.
Mendeleev’s periodic law.
Answer:
Mendeleev stated a periodic law. The law states that “Properties of elements are periodic function of their atomic masses.”
⇒ Mendeleev arranged the elements according to their properties and in order of increasing atomic weights.
⇒ In the Mendeleev’s periodic table, vertical columns are called groups and horizontal rows are called periods.
⇒ Atomic masses of some elements were rediscovered so as to give them proper place in the periodic table.
⇒ Mendeleev kept vacant places in the periodic table for elements not discovered till then.
